Post Editorial Says Study 'Demolishes' Anti-Charter Debates

That report on New York City's charter schools continues to draw media attention. The Washington Post, in a Sunday editorial, goes so far as to say that the report "demolishes the argument" that charter schools cream the best students from traditional public schools. It also says:

This evidence should spur states to change policies that inhibit charter-school growth. It also should cause traditional schools to emulate practices that produce these remarkable results.

That kind of enthusiam might be a little premature. New York is just one city—and one that charter school experts tell me is known for the quality of its authorizing system for charter schools. What's more, the promising practices that the report identifies were merely linked to higher student achievement. Even study author Caroline M. Hoxby points out that her findings don't suggest that things like longer school days, performance pay, or strict classroom management caused the charter school students to outperform their peers in traditional schools.

Some of the excitement over Hoxby's findings stem from her choice of study design. Hoxby used a randomized control trial to compare the achievement of students who won a charter-school seat in a lottery to that of students who applied but failed to land a spot. Experts consider this methodology to be the "gold standard" for research on effectiveness, but, as this blogger points out in a blog called—what else?—"More Thoughtful," even randomized studies have their limitations.

There've been lots of comments, too, in the blogosphere about Hoxby's penchant for finding positive results in studies involving free-market education strategies. That may be cause for skepticism, I say, but is it a good enough reason to dismiss the new findings out of hand?

It strikes me that, for all its merits, the study does not clearly address the relative quality of charter & traditional public schools. It could suggest that motivated students will do better among similarly motivated students, because they would benefit from peer effects. For some charter supporters, that's more than enough justification.

This study, like that of Professor Fryer in regard to the Harlem Children's Zone, indicates that longer school hours appear to be related to higher achievement. This is a well-known effect, without regard to school administrative structure. The policy lesson is that students should have available to them more hours per day, week (Saturdays), and year (summer school). Whether or not charter schools are more effective in delivering this appropriate amount of learning time is not a finding of the studies discussed to date.

Commenters,
All of you make good points. Peer effects, more time, and school quality are all important factors to consider.
I find the issue of time particularly frustrating because it's so hard to measure. If regular public schools just stayed open longer, as President Obama seemed to suggest in his remarks the other day, would they get the same results?